When things gets busy in Iceland, they mean it. At least that is the case now. This also the reason why I do not trust the quiet times in Iceland.
A earthquake with the size of ML3.4 took place 25 km east of Grímsey Island in the TFZ at 21:46 UTC. But that is an non-volcanic zone that bridges the eastern volcanic zone with the North-Atlantic rift zone. This earthquake had an earthquake with the size of ML2.9 taking place before the larger one. That was an pre-earthquake most likely. But it seems that an earthquake swarm is also starting in TFZ as it has done close to Krísuvík volcano on the Reykjanes Ridge. I do not know if this earthquake was felt or not.
I am going to update this blog post if I need to.
Update 1: The location of this earthquake. So far there have not been any aftershocks following the ML3.4 earthquake. Its depth was at 11.5 km. This earthquake does not appear clearly on my geophones due to the distance involved (over 200 km).
The location of the ML3.4 earthquake on TFZ. Copyright of this picture belongs to Iceland Met Office.
Blog post updated at 22:22 UTC.
At 21:12 UTC on 3. January 2012 an earthquake with the automatic size of ML3.6 did happen in Krísuvík volcano. I do not yet know if this earthquake was felt in the nearby area. But I assuming that it has done so.
This earthquake did appear clearly on my geophones. Both in north and south Iceland. They can be viewed here. I am going to update this blog post as I know more. But this seems to be an start of earthquake swarm in Krísuvík volcano.
Update 1: It has been confirmed that this earthquake was felt in Reykjavík and nearby area. The automatic depth of this earthquake was 14.2 km according to Iceland Met Office.
Update 2: Earthquake swarm has started in Krísuvík volcano. The largest earthquake in this earthquake swarm after the main earthquake is ML1.1 in size. Larger earthquakes however might happen at any time in this earthquake swarm. But that is at least the experience so far.
Update 3: Here are the traces of the earthquake. Sorry. But for the moment there are no high resolution pictures available as my main earthquake computer is offline until I move back to Denmark. See this blog post here for more details on that.
The location of the ML3.6 to ML3.7 earthquake in Krísuvík volcano. Copyright of this picture belongs to Iceland Met Office.
The ML3.6 earthquake as it did appear on Eyrarbakki geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.
The ML3.6 earthquake as it did appear on the Heklubyggð geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.
The ML3.6 earthquake as it did appear on the Hvammstangi geophone. This picture is released under Creative Commons Licence. Please see the CC Licence web page for more detail.
Blog post updated at 21:38 UTC.
Blog post updated at 21:45 UTC.
Blog post updated at 22:15 UTC.
I have been seeing some rumors about Hekla volcano might be about to erupt. This is wrong. For the moment Hekla volcano is quiet as it has been since the last eruption in the year 2000. For few years Hekla volcano did erupt for about every 10 years. That might have change already. Nobody is sure on that now. But one thing is clear Hekla volcano is going to erupt one day. But when is always the question.
People have been speculating on the earthquakes west of Hekla volcano. This earthquakes do not belong to Hekla volcano. They are part of activity in the SISZ (South Icelandic Seismic Zone). Earthquakes in this area tectonic in nature, not volcanic. So in worst case, this earthquakes might be sign of new major earthquake preparing to take place some day in the future.
For the moment however. Everything is quiet in Hekla volcano.